<ion-header>
  <ion-toolbar>
    <ion-buttons slot="start">
      <ion-back-button defaultHref="/tabs/tab1"></ion-back-button>
    </ion-buttons>
    <ion-title>loading</ion-title>
  </ion-toolbar>
</ion-header>

<ion-content padding>
  

    <ion-button (click)="presentLoading()">
      presentLoading
    </ion-button>

    <ion-button (click)="presentLoadingWithOptions()">
      presentLoadingWithOptions
    </ion-button>
</ion-content>